BackgroundEarly parent-child interactions have a critical impact on the developmental outcomes of the child. It has been reported that infants with a family history of autism and their parents may engage in different patterns of behaviours during interaction compared to those without a family history of autism. This study investigated the association of parent-child interactions with child developmental outcomes of those with typical and elevated likelihood of autism. MethodThis longitudinal study investigated the relationship between global attributes of parent-child interaction and the developmental outcomes of infant siblings with elevated likelihood (EL: n = 29) or typical likelihood (TL: n = 39) of developing autism. Parent-child interactions were recorded during a session of free-play when the infants were six months of age. Developmental assessments were carried out when the children were 12 and 24 months of age. ResultsThe intensity of mutuality was significantly higher in the TL group than in the EL group, and developmental outcomes were poorer in the EL group when compared to the TL group. Positive associations between parent-child interaction scores at six months and developmental outcomes at 12 months were observed only in the TL group. However, in the EL group, higher levels of infant positive affect and attentiveness paid to the caregiver is associated with lower autism symptoms. Due to the sample size and design of the study, the findings must be viewed as indicative. ConclusionThis preliminary investigation demonstrated differences in the association between parent-child interaction quality and developmental outcomes for children with typical and elevated likelihood for autism. Future studies should combine micro-analytic and macro-analytic approaches to parent-child interaction to further examine the nature of this relationship.